The Snap to Contour option will snap the selected anchor point to any line you position it on—see Contour Editor Options.

•

The Snap and Align option lets you snap the selected anchor point to any existing line while displaying temporary rulers as a guide that you can also snap your anchor point to—see Contour Editor Options.

•

The Snap to Grid option snaps your selection according to the currently enabled grid.

The Apply to Line and Colour Art option uses the concept of Line Art and Colour Art layers. Use this option to apply an action such as selecting, resizing or erasing a drawing on both Line Art and Colour Art layers, as well as the Overlay and Underlay layers.